Tridentoquinone (1), the main pigment of Suillus tridentinus, is accompanied by the known meroterpenoid bolegrevilol (3) and a dimer, tridentorubin (5). The absolute configuration of 1 was unambiguously established by a single-crystal X-ray analysis of the corresponding (–)-camphanoate. The structure of 5 was elucidated by 2D NMR techniques including a 2D INADEQUATE experiment. Feeding experiments